Apparatus for atomizing a liquid in a vacuum



y 27, 9 "L5. DICKINSON 2,836,464

APPARATUS FOR ATOMIZING A LIQUID IN A VACUUM 2 Sheets-Sheet 1 Filed 001;. 26, 1954 Inventor Thomas S. Dickin solv Attorney May 27, 1958 T. s. DICKINSON 2,336,464

APPARATUS FOR ATOMIZING A LIQUID IN A VACUUM Filed Oct. 26, 1954 2 Sheets-Sheet 2 Inventor Thomas SDickinson A item 2 y United States Patent APPARATUS FOR ATOMIZING A LIQUID IN A VACUUM Thomas S. Dickinson, Radcliffe, England, assignor to The General Engineering Company (Radciiffe) Limited, Radcliffe, England, a British company Application October 26, 1954, Serial No. 464,829

2 Claims. (Cl. 29963) This invention relates to apparatus for atomizing a liquid in a vacuum and is particularly, though not exclusively, applicable to the process of, and apparatus for, the dehydration and deaeration of transformer or impregnating oils as used in the electrical industry.

Modern developments in the technique of preparing such impregnants includes the use of a vacuum of a very high order, such as 20 microns, or 0.02 mm. of mercury absolute pressure, and in consequence a recent development has been to place as many parts as possible within the vacuum vessel so that there will be fewer external parts such as valves and piping and circulating and transfer pumps, which have to be proof, or sealed, against leakage of air into the vessel, as otherwise it becomes difficult, if not impossible to obtain or maintain the required vacuum.

Also, it is known to atomise the impregnant mechanically within the vacuum vessel so as to assist and accelcrate the dehydration and deaeration, using an electric motor to rotate a centrifugal sprayer. Owing to the high degree of vacuum and the fact that the impregnant is usually heated during such treatment it has been found impracticable to place such electric motor within the vacuum vessel itself and one of the major problems with such apparatus is the sealing of the glands around the shaft connecting the motor outside the vessel with the centrifuge or sprayer within the vessel.

The present invention is based upon the appreciation of the fact that very little power should be required to drive the sprayer or centrifuge at the required speed, provided the high frictional resistance of the tight glands hitherto used to seal the shaft could be eliminated, with the further appreciation that the means for doing so is already available in the means normally provided withv such apparatus for introducing the liquid thereto or/and circulating it therein.

According to the present invention, apparatus for atomizing a liquid in a vacuum including a rotary sprayer or atomizer mounted in a vacuum vessel and means for pumping or admitting the liquid to the sprayer is characterised in that turbine means are provided for rotating the sprayer or atomizer, actuated by the momentum of the liquid on admission to the apparatus and/ or during circulation :therethrough. The liquid, after passing through the said turbine driving means preferably passes direct to the sprayer or atomizer.

The invention will be described further, by way of example, with reference to the accompanying drawings in which:

Fig. 1 is a sectional elevation through one preferred form of atomizer according to the present invention,

Fig. 2 is a plan view, partly in section of the arrangement shown in Fig. 1.

In the example of the invention illustrated the sprayer or atomizer comprises a cylindrical casing 10 having a flange 11 about half way of its length by which it is adapted to be mounted on the top of a vacuum vessel 12. Within the casing 10 is mounted a shaft, 13 on ice anti-friction bearings 14, 15 located in housings 16, 17 respectively at each end of the casing, the upper housing 16 being formed in a detachable end cover 18 the latter having an extended hollow hub 19 adapted to hold a stationary sealing element 29 secured by means of a cover whereby the upper end of the casing may be, cffectively sealed over the end of the shaft 13. In the side of the casing 10, and above the flange 11 there is a side opening 21 surrounded by a facing 22 to receive a flange 23 of a nozzle 24 complementary to an impeller or Pelton Wheel 25 mounted on the shaft 13. At its lower end, the shaft 13 is provided with a cup-like sprayer or centrifuge 26 of the kind already known for the purpose, and liquid upon injection through the nozzle 24 and .after striking the impeller 25 is able to pass down thereto through apertures 27 in the housing 17 for the lower anti-friction bearing 15 for the shaft 13.

In use, liquid is pumped or admitted to the vacuum vessel through the nozzle 24 and the momentum of the liquid is used to cause the shaft 13 to rotate at high speed. The liquid, after thus expending its energy, passes down by gravity to the lower end of the casing 10 into the cup-like sprayer or centrifuge 26 by which it is atomized in the required manner and passes into the vacuum vessel 12 through a series of orifices 28.

if desired, the liquid may be caused to pass more than once through the impeller or turbine-driven sprayer, each time providing the energy for the rotation of the sprayer or centrifuge 26. By such construction the previous problem of sealing the shaft of the sprayer by means of glands is eliminated as is also the need for an electric motor located either within or externally of the vessel for driving the said shaft.

The invention is obviously not limited to all the details of the example above described, in so far as they may be modified without departing from the scope of the invention. For example, any suitable form of liquid turbine other than the Pelton Wheel above described could be used, and after the first admission, the liquid could be caused to pass again to the sprayer by the circulating means normally provided with such apparatus. Instead of the liquid passing direct from the turbine to the centrifuge or sprayer it could pass directly into the vessel and the liquid may be separately piped to the sprayer or centrifuge if a smaller or larger volume of liquid is required thereat according to the power available and the degree of atomization required.

I claim:

1. Apparatus for atomizing a liquid in a vacuum comprising an elongated vertical casing, bearings at the ends of said casing, a shaft mounted axially in said casing and held in said bearings, an impeller fixed on an intermediate portion of said shaft, a nozzle in the side of said casing adjacent to said impeller and adapted to cause fluid to impinge on said impeller to rotate said shaft, a seal at the upper end of said casing, a transverse flange extending from an intermediate portion of said casing, a vacuum vessel, said flange being secured to said vessel with the lower portion of said casing being within said vessel, the lower end of said shaft extending below the lower end of said casing, a cup-shaped sprayer fixed on the lower end of said shaft, and an opening between said cup and casing to permit fluid from said casing to enter said cup by gravity flow.

2. Apparatus for atomizing a liquid in a vacuum comprising an elongated vertical casing, bearings .at the ends of said casing, a shaft mounted axially in said casing and held in said bearings, an impeller fixed on an intermediate portion of said shaft, a, nozzle in the side of said casing adjacent to said impeller and adapted to cause fluid to impinge on said impeller to rotate said shaft, a seal at the upper end of said casing, a transverse flange extending from an intermediate portion of said casing, a vacuum vessel, said flange being secured to said vessel with the lower portion of said casing be afing Within-said vessel, said nozzle being above said flange,

e e thelower end of said shaft extending below the lower end fof said casing, 21 cup-shaped sprayer fixed on the lower 2 end of said shaft, and an opening between said cup and casing'to permit fluid from said casing to enter said cup by gravity flow;

f n s ted. ehefile we w UNITED STATES PATENTS Helmer Nov. 9, 1926 v Shanklin July 30, 1935 Igarashi etal. June 9, 1936 Hoy et a1. Nov. 1, 1938 Suss 1 ...7 Mar, 4, 1941 Shearman Oct. 9,1951 

